KR100401300B1 - Core fanctionalised star block copolymers - Google Patents

Abstract

The present invention provides a core functionalized star block copolymer formed of i) at least one block of vinyl aromatic hydrocarbons, and / or ii) at least one block of conjugate dienes and iii) a polyalkenyl aromatic coupling agent, wherein the core functional The formation is obtained by reacting the asymmetric bi- or multifunctional capping agent with the star polymer core.

Description

Core functionalized star block copolymers {CORE FANCTIONALISED STAR BLOCK COPOLYMERS}

The present invention relates to core functionalized star block copolymers and methods for preparing them. More particularly, the present invention relates to star block copolymers having a bi- or multifunctional capping agent extending from the core of the block copolymer.

Star block copolymers of conjugated dienes and / or vinyl aromatic hydrocarbons are well known and have been produced commercially for many years. The block copolymers are generally prepared by anionic polymerization of monomers to form living polymer arms, which are then coupled with a polyfunctional coupling agent, which is generally a polyalkenyl aromatic compound such as divinyl benzene. After the arm is fully coupled to the core, the core is still "living" and can react further. Living cores are terminated by adding alcohol, water, acid or other acidic (protic) species.

For many reasons, it would be advantageous to introduce polar or low surface energy functionality into the star polymer. For example, polar functionality increases the adhesion of these polymers to polar surfaces and makes them more widely used in adhesives or release agents. The polymer can also be used in asphalt variants.

US 4,417,029 describes star block copolymers having functional groups associated with the nucleus of the copolymer. Most inducers described in this patent specification are multifunctional compounds. In each case, this polyfunctional group can often be changed to a less desirable extent by the induction reaction itself. Some examples of bifunctional inducers provided are symmetric. In other words, all functional groups are identical. In this case, since the reaction is purely a statistical reaction, undesirable crosslinking is likely to occur. Crosslinking can be avoided by using large amounts of inducers, but this creates the disadvantage of removing large amounts of unreacted excess inducers.

The present invention provides a method of avoiding these disadvantages. Since the capping agent extends from the polymer core, the desired functionality and also high reactivity for the capping reaction and contain the desired functional groups and other functional groups, the reaction that causes the desired functional groups to extend from the core occurs with high selectivity. This is obtained without altering the chemical structure of the desired functional group and without unwanted crosslinking reactions. Furthermore, the present invention is anionic polymers, ie fluorine, NR ₂ , (OCH ₂ CH ₂ ) _x OR, because the anionic polymers are non-reactive to the softened core and are destroyed by killing through metallization (softening). And incorporation of functionality that was previously impossible to incorporate into metallocenes.

The present invention comprises a core functionalized block copolymer formed of i) at least one block of vinyl aromatic hydrocarbons, ii) at least one block of conjugated dienes and iii) a polyalkenyl aromatic coupling agent; a core functionalized star block copolymer formed of i) at least one block of vinyl aromatic hydrocarbons and iii) a polyalkenyl aromatic coupling agent; And ii) a core functionalized star block copolymer formed of at least one block of conjugate diene and iii) a polyalkenyl aromatic coupling agent, reacting with the polymer core and attaching a capping agent molecule to the core via a second functional group. The core functionalization is obtained by incorporating a second type of functional group and a first type of functional group extending from the core and reacting the asymmetric bi- or polyfunctional capping agent with the star polymer polymer core (all of which are not identical). It provides a block copolymer. The star block copolymers of the present invention provide novel functionalized star block copolymers having polar or low surface energy functionality extending from the core of the star block copolymer. In a preferred embodiment, the star block copolymer contains from 0.05 to 10% by weight of functional groups of the first type. The polymer is formed of at least one vinyl aromatic hydrocarbon and / or at least one conjugated diene.

The star block copolymers are asymmetric incorporating a second type of functional group that will react with the living core and attach molecules to the core via the second functional group and the desired functionality extending from the core (the first type of functional group)-or It can be prepared by reacting a multifunctional capping agent with a living property block copolymer core. Suitably, 0.05-10% by weight of capping agent is used.

Polymers containing ethylenic unsaturations can be prepared by copolymerizing one or more polyolefins, in particular diolefins. Copolymers may, of course, have linear, constellation or radicals as well as random, tapered, block or combinations thereof.

Polymers containing ethylenic unsaturations can be prepared using anionic initiators or polymer catalysts. The polymer may be prepared using agglomerate, solution or emulsion techniques. In any case, the polymer containing at least ethylenic unsaturation will generally be recovered as a solid, liquid such as debris, powder, pellets, or the like. Polymers containing ethylenic unsaturations are available from several suppliers.

In general, when used in solution anionic techniques, copolymers of conjugated diolefins are monomers or monomers to be polymerized simultaneously or in succession with anionic polymerization initiators such as Group IA metals, their alkyl, naphthalides, biphenyl or anthracenyl derivatives. By contacting them. Preference is given to using organic alkali metal (eg sodium, lithium or potassium) compounds in suitable solvents at temperatures in the range of -150 ° C-300 ° C, preferably in the range of 0 ° C-100 ° C. Particularly effective anionic polymerization initiators are organolithium compounds having the general formula:

Wherein R is an aliphatic, cycloaliphatic, aromatic or alkyl-substituted aromatic hydrocarbon radical having 1-20 carbon atoms and n is an integer from 1-4.

Conjugate diolefins that can be polymerized anionic include those conjugate diolefins containing from about 4 to about 24 carbon atoms, such as 1,3-butadiene, isoprene, pipeylene, methylpentadiene, phenyl-butadiene, 3, 4-dimethyl-1,3-hexadiene, 4,5-diethyl-1,3-octadiene and the like. Isoprene and butadiene are preferred conjugate diene monomers for use in the present invention. Vinyl aromatic hydrocarbons may also be included in the block copolymers. Styrene, alphamethyl styrene, and other substituted styrenes can be used, but styrene is preferred. The polymers of the present invention may suitably comprise up to 50% by weight vinyl aromatic hydrocarbons.

The star polymer of the present invention is a block copolymer having at least three arms comprising at least one block of vinyl aromatic hydrocarbon and / or at least one block of conjugated diene attached to the central core. The polymer may suitably have up to 30 or 40 arms.

As indicated above, the star polymer of the present invention is prepared by coupling a polymer arm using a multifunctional coupling agent or coupling monomer. Preferred coupling agents are polyalkenyl aromatic coupling agents such as those described in US Pat. No. 4,010,226, US Pat. No. 4,391,949 and US Pat. No. 4,444,953, which are incorporated herein by reference. US 5,104,921, which is also incorporated herein by reference, fully describes the polyalkenyl aromatic compounds in lines 12 and 13. Divinyl aromatic hydrocarbons containing up to 26 carbon atoms per molecule are preferred, in particular divinyl benzene to meta or para isomers and commercial divinyl benzene, which is a mixture of these isomers, are also quite satisfactory. After the polymerization is substantially complete, the coupling agent is preferably added to the living polymer. The amount of coupling agent varies widely, but preferably at least one equivalent per equivalent of unsaturated living polymer to be coupled is used. The coupling reaction is generally carried out in the same solvent for the polymerization reaction. The temperature varies widely, such as in the range 25 ° -95 ° C.

In general, any solvent known in the prior art useful in the preparation of such polymers may be used. Suitable solvents include straight and branched chain hydrocarbons such as pentane, hexane, heptane, octane and the like, as well as alkyl-substituted derivatives thereof; Cycloaliphatic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane and the like, as well as alkyl-substituted derivatives thereof; Aromatic and alkyl-substituted derivatives thereof; Aromatic and alkyl-substituted aromatic hydrocarbons such as benzene, naphthalene, toluene, xylene and the like; Hydrogenated aromatic hydrocarbons such as tetralin, decalin and the like; Linear and cyclic ethers such as methyl ether, methyl ethyl ether, diethyl ether, tetrahydrofuran and the like.

More particularly, the star polymers according to the invention are prepared by anionic polymerization of monomers in hydrocarbon solvents at temperatures of up to 100 ° C., preferably in the range of 25-80 ° C., using alkyl lithium initiators. Living polymer chains are generally coupled by addition of divinyl monomers to form star polymers. Additional monomers may or may not be added to grow more branches or to finally functionalize the polymer.

It is important to couple until it is almost complete as possible. Therefore, the coupling reaction will not end. There must be at least one active site on the coupling agent core of the polymer. The asymmetric bi- or multifunctional capping agent is then introduced into and reacted with the polymer. In general, the conditions are 25-90 ° C. for up to 1 hour and 0.05-10% by weight of the medicament is used. The exact method of reaction depends on the nature of the capping agent.

Suitable capping agents which can be used according to the invention are perfluoroaldehydes, perfluoroketones, perfluoroalkanoylchlorides, perfluoroesters, perfluoroetheresters, formyl esters, polyoxyalkenylene esters, amino Aldehydes, metallocenealdehydes, epoxides of aldehydes, diepoxides of ketones, and epoxide derivatives of silanes. Metallocenes are organometallic coordination compounds obtained as cyclopentadienyl derivatives of transition metals. Two types of metallocenes useful herein are (1) dicyclopentadienyl-metal having general formula (C ₅ H ₅ ) ₂ M and (2) general formula (C ₅ H ₅ MR _1-3 ), wherein Is a monocyclopentadienyl-metal compound having R, CO, NO or alkyl.

Perfluoro capping agents add fluorine functionality to the core of the polymer. Formyl ester capping agent adds ester functionality. Polyoxyalkenyl capping agents add functionality such as polyoxyalkenylene, ie polyoxyethylene, polyoxypropylene and the like. Amino aldehydes add amino functionality. Metallocene aldehydes add metallocene functionality. Diepoxide adds epoxide functionality. Preferred coupling agents are those having perfluoro groups, polyether groups, amino groups and epoxides.

It is highly desirable that the asymmetric capping agent be selected such that the reactivity of the first type of functional group, preferably extending from the polymer core, is much less than the reactivity of the second type of functional group reacted with the polymer core to attach to the molecule. Clearly, this is important for increasing the selectivity of the desired reaction when opposed to the opposite reaction. Table 1 shows several examples of two- or multifunctional capping agents extending from the polymer core, leaving the desired functionality unchanged.

Table 1

After the capping agent reaction has proceeded, the reaction mixture is terminated with proton sources such as methanol, water, acetic acid and the like. The polymer is then separated from the polymer cement by conventional means.

Star polymers capped with polyesters are useful in emulsions and water dispersions. Amines and epoxides are useful for bonding to polar surfaces. Polymers capped with perfluoro groups are useful in applications requiring low surface energy, such as non-tacky or release applications.

Example

Example 1

70% of the arms are styrene-isoprene diblocks (11,000 and 60,000 peak molecular weight, respectively, as determined by gel permeation chromatography), and 30% of the arms are isoprene blocks (60,000 peaks, as determined by gel permeation chromatography). The synthesis | combination of a star-shaped polymer which is molecular weight) is described below. The polymers that can be used to couple these arms to the core of unterminated divinyl benzene and react with the capping agent can be represented by the following general formula:

This master batch was synthesized to provide a living coupled star polymer for the continuous core functionalization reaction. The polymer had 15-30 arms.

326.6 kg of cyclohexane and 4 kg of styrene were combined and 0.37 mole of secondary-butyl lithium was added and the temperature was increased to 50 ° C. and held for 30 minutes to polymerize styrene and produce living polystyryl lithium. Then, 0.16 mol of secondary-butyl lithium and 32.2 kg of isoprene were added to grow the SI (styrene-isoprene) and I (isoprene) arms in parallel. The polymerization was carried out at 60 ° C. for 60 minutes. Then, 1.59 moles of divinyl benzene (DVB) were added and the coupling reaction proceeded at 60 ° C. for 1 hour. This gave a DVB: lithium molar ratio of 3: 1.

The coupling reaction was not terminated. The batch was divided into several parts to react with various functionalized capping agents.

Example 2

54.5 L of cement containing living star polymer was transferred to a pressure vessel. The cement contained 52 mmol of living polymers. To this, 10.2 g (52 mmol, 1: 1 aldehyde: lithium ratio) of pentafluorobenzaldehyde was added. The vessel was spun on a mechanical roller for 30 minutes at a temperature of 50 ° C. and then the reaction was terminated with methanol.

The cement was vapor coagulated to yield about 3.63 kg of fluorinated core functionalized star polymer. Elemental analysis showed that the product contained 0.22% by weight of fluorine. This implies essentially a complete capping of the DVB core with C ₇ F ₅ HO since the theoretical value of fluorine is 0.15% by weight.

Example 3

3 liters (2400 g) of living cement of Example 1 were transferred to a 4.54 liter jar equipped with a septum. The cement contained 3.5 mmol of living polymer. To this, 2.1 g (5 mmol) of methyl perfluoro octanoate was added. The jar was placed on an experimental shaker and allowed to react at 50 ° C. for 30 minutes, then terminated with methanol and coagulated with isopropyl alcohol. The product was collected by filtration and the vacuum dried at 50 ° C. overnight. 0.23 kg of fluorinated core functionalized star polymer was obtained. Elemental analysis analyzed 0.24% by weight of fluorine, while the total possible theoretical value at the ratio of 1 mole of perfluoro compound per mole of lithium would be 0.4% by weight. Thus, the reaction proceeded and was 60% complete.

Example 4

This experiment was carried out according to the procedure of Example 3 except that the capping agent was perfluorooctanoyl chloride. By elemental analysis, 0.39% by weight of fluorine was analyzed, while the total possible amount would essentially be 0.4% by weight when the reaction was complete.

Example 5

This experiment was performed according to the procedure of Example 3 except that the capping agent was F- [CF (CF ₃ ) CF ₂ O] ₄ -CF (CF ₂ ) CO ₂ CH ₃ . By elemental analysis, 0.22% by weight of fluorine was analyzed, while the theoretical total possible amount was 0.8% by weight with 27% conversion.

Example 6

This experiment is performed according to the procedure of Example 3, except that the capping agent is methyl-4-formyl benzoate and 6.4 mmol of the capping agent is used. The following functional group by this reaction:

Wherein R is methyl is incorporated into the core of the star polymer.

Example 7

This experiment is performed according to the procedure of Example 3, except that the capping agent is R- (OCH ₂ CH ₂ ) ₂₅ -OCH ₂ CO ₂ R and 2 mmol molar capping agent is used. In this reaction, polyethylene oxide having a molecular weight of 1100 is incorporated into the core of the star polymer.

Example 8

This experiment is performed following the procedure of Example 3 except that the capping agent is 4-dimethylaminobenzaldehyde and 6.4 mmol of the capping agent is used. The following functional group by this reaction:

In which R is methyl is incorporated into the core of the polymeric polymer.

Example 9

This experiment is carried out according to the procedure of Example 3, except that the capping agent is ferrocene carboxyaldehyde and 6.4 mmol of the capping agent is used. In this reaction, -Fe (cyclopentadiene) ₂ functionality is incorporated into the core of the aqueous phase polymer.

Claims (10)

i) at least one block of vinyl aromatic hydrocarbons selected from styrene or substituted styrenes, ii) at least one block of conjugated dienes containing 4-24 carbon atoms, and iii) polyalkenyl containing up to 26 carbon atoms Core functionalized star block copolymers formed with aromatic coupling agents; a core functionalized star block copolymer formed of at least one block of vinyl aromatic hydrocarbons selected from styrene or substituted styrenes and iii) polyalkenyl aromatic coupling agents containing up to 26 carbon atoms; or ii) a core functionalized star block copolymer formed of at least one block of conjugated diene containing 4-24 carbon atoms and iii) a polyalkenyl aromatic coupling agent containing up to 26 carbon atoms, Core functionalization is obtained by reacting the star-shaped polymer core with an asymmetric bi- or polyfunctional capping agent, in which not all of the functional groups are the same, wherein the bi- or polyfunctional capping agent is applied to the polymer core and the first type of functionality extending from the core. A star-shaped block copolymer incorporating a functional group of the second type to react and attaching the capping agent molecule to the core via the second functional group. The method of claim 1, wherein the capping agent is perfluoroaldehyde, perfluoroketone, perfluoroalkanoyl chloride, perfluoroester, perfluoroetherester, formyl ester, polyoxyalkenylene ester, aminoaldehyde, metal A block copolymer selected from the group consisting of rosene aldehyde, epoxide of aldehyde, diepoxide of ketone, and epoxide derivative of silane. The block copolymer according to claim 1, which contains 0.05 to 10% by weight of functional groups of the first type. The block copolymer according to any one of claims 1 to 3, wherein the vinyl aromatic hydrocarbon is styrene. 4. The block copolymer of any one of claims 1 to 3, wherein the conjugate diene is isoprene or butadiene. The block copolymer according to any one of claims 1 to 3, comprising 50% by weight or less of vinyl aromatic hydrocarbons. (a) at least one block of vinyl aromatic hydrocarbon, or at least one block of conjugate diene, or at least one polymer arm of at least one block of vinyl aromatic hydrocarbon and at least one block of conjugate diene by anionic polymerization Manufacturing, (b) coupling the polyalkenyl aromatic coupling agent and the polymer arm and not terminating the coupling reaction, (c) Asymmetric, but not all, functional groups that incorporate a second type of functional group that reacts with the polymer core and a first type of functional group extending from the core to attach the capping agent molecule to the core via the second functional group. Or capping the core of the living star polymer by reacting the polyfunctional capping agent with the core of the living star polymer, (d) A method for producing a core functionalized star block copolymer consisting of terminating the capping reaction and recovering the polymer. 8. The method of claim 7, wherein the capping agent is perfluoroaldehyde, perfluoroketone, perfluoroalkanoylchloride, perfluoroester, perfluoroetherester, formyl ester, polyoxyalkenylene ester, aminoaldehyde, metal A process selected from the group consisting of rosene aldehyde, epoxide of aldehyde, diepoxide of ketone and epoxide derivative of silane. The process according to claim 7 or 8, wherein 0.05-10% by weight of capping agent is used in step (c). The process according to claim 7 or 8, wherein the temperature applied in step (b) is in the range of 25 to 95 ° C.